US5900290A - Method of making low-k fluorinated amorphous carbon dielectric - Google Patents
Method of making low-k fluorinated amorphous carbon dielectric Download PDFInfo
- Publication number
- US5900290A US5900290A US09/023,382 US2338298A US5900290A US 5900290 A US5900290 A US 5900290A US 2338298 A US2338298 A US 2338298A US 5900290 A US5900290 A US 5900290A
- Authority
- US
- United States
- Prior art keywords
- pecvd
- chamber
- substrate
- silane
- amorphous carbon
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02107—Forming insulating materials on a substrate
- H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
- H01L21/0226—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process
- H01L21/02263—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase
- H01L21/02271—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition
- H01L21/02274—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition in the presence of a plasma [PECVD]
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/20—Deposition of semiconductor materials on a substrate, e.g. epitaxial growth solid phase epitaxy
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
- C23C16/26—Deposition of carbon only
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02107—Forming insulating materials on a substrate
- H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
- H01L21/02112—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer
- H01L21/02115—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material being carbon, e.g. alpha-C, diamond or hydrogen doped carbon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02107—Forming insulating materials on a substrate
- H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
- H01L21/02112—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer
- H01L21/02118—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer carbon based polymeric organic or inorganic material, e.g. polyimides, poly cyclobutene or PVC
- H01L21/0212—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer carbon based polymeric organic or inorganic material, e.g. polyimides, poly cyclobutene or PVC the material being fluoro carbon compounds, e.g.(CFx) n, (CHxFy) n or polytetrafluoroethylene
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02107—Forming insulating materials on a substrate
- H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
- H01L21/02205—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates the layer being characterised by the precursor material for deposition
- H01L21/02208—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates the layer being characterised by the precursor material for deposition the precursor containing a compound comprising Si
- H01L21/02211—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates the layer being characterised by the precursor material for deposition the precursor containing a compound comprising Si the compound being a silane, e.g. disilane, methylsilane or chlorosilane
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/312—Organic layers, e.g. photoresist
- H01L21/3127—Layers comprising fluoro (hydro)carbon compounds, e.g. polytetrafluoroethylene
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/314—Inorganic layers
- H01L21/3146—Carbon layers, e.g. diamond-like layers
Definitions
- the invention relates to a method of forming an interlevel dielectric of the type used in interconnect structures of integrated circuits, and more paticularly to a plasma enhanced chemical vapor deposition method of forming a low-dielectric-constant insulating material.
- interconnects lines, vias, etc.
- RC resistance-capacitance
- Capacitance can be reduced by employing lower dielectric constant (i.e., lower-k) dielectric materials.
- Fluorocarbon polymers have been studied for more than two decades and most of their applications is for the use of coating materials to protect plastics, fibers, and metals. It is known that a-F:C films can be fabricated using plasma enhanced CVD ("PECVD"). Early experience with a-F:C showed that the films deposited at room temperature could be deposited with a dielectric constant as low as 2.1 and a thermal stability ⁇ 300° C. Further experimentation showed that if the a-F:C films were deposited at higher substrate temperatures, the thermal stability could be improved up to 400° C., but the dielectric constant increased above ⁇ 2.5.
- PECVD plasma enhanced CVD
- Table I illustrates how the dielectric constants and thermal stabilities of several members of carbon family compare to a-F:C. It shows that the dielectric constant can be lowered if carbon films contain higher fluorine concentrations.
- the fluorine concentration of a-F:C film depends on the fluorine to carbon ratio in the discharge, which is established by the feed gas composition, RF power input, substrate temperature, and total pressure.
- the thermal stability is closely related to the degree of crosslinking among the polymer chains. The greater the degree of crosslinking, the more tightly bound the structures are, and the higher the thermal stability.
- a PECVD process either raising substrate temperature, enhancing ion bombardment, or applying low frequency plasma energy can increase the crosslinking in a-F:C films. Higher temperature deposition has the disadvantage of inevitably reducing the fluorine concentration, thereby increasing the dielectric constant.
- the disadvantages of high temperature deposition processes are that it not only increases the dielectric constant, but also leads to poor adhesion to SiO 2 and Si 3 N 4 due to increased thermal stress, and also causes higher leakage current in the films. It appears that a lower deposition temperature is desirable.
- Fluorinated amorphous carbon has a dielectric constant k below 3.0 and, depending on the proportion of fluorine (F) in the film, can have a k in the range of 2.0 to 2.5.
- a major problem with a-F:C is its poor thermal stability. It has heretofore not been possible to prepare a-F:C films with suitable low-dielectric-constant properties (k less than 2.5), and a thermal stability above 400° C. Temperatures in the sintering range (450° C.) typical for manufacturing ULSI chips cause excessive shrinkage of the a-F:C film, probably due to fluorine volatilization. Mechanical strength and adhesion problems also are obstacles to the use of a-F:C as an interconnect dielectric in high-density integrated circuits.
- PECVD plasma enhanced chemical vapor deposition
- a plasma enhanced chemical vapor deposition (PECVD) process for depositing a dielectric material on a substrate for use in interconnect structures of integrated circuits.
- the method comprises steps which include positioning the substrate in a PECVD chamber and heating the substrate to a temperature above 200° C.
- a flow of fluorine containing gas (FCG) and carbon containing gas (CCG) is introduced into the chamber under sufficient applied energy to form a fluorine and carbon gas plasma in the chamber.
- FCG fluorine containing gas
- CCG carbon containing gas
- the ratio of FCG to CCG is selected to deposit fluorinated amorphous carbon on the substrate.
- a flow of silane (SiH 4 ) is introduced into the chamber.
- the silane increases the thermal stability of the fluorinated amorphous carbon deposited on the substrate.
- FCG fluorine containing gas
- C 4 F 8 carbon containing gas
- CH 4 methane
- a suitable ratio of FCG to CCG for the deposit of fluorinated amorphous carbon on the substrate is generally in the range of between 1/1 and 30/1 (FCG/CCG) and, more preferably, generally in the range of 5/1 to 15/1.
- the percentage of silane gas in the mixture of FCG, CCG, and silane gases introduced into the PECVD chamber is preferably generally in the range of 1% to 15%.
- the ambient pressure maintained in the PECVD chamber during the introduction of FCG, CCG, and silane into the chamber is preferably generally in the range of 0.3 Torr to 2.0 Torr.
- plasma energy in the form of high frequency (HF) plasma energy
- HF high frequency
- LF low frequency
- the HF energy has a frequency of 13.56 MHz and is preferably applied at an energy level of between 0.5 Watts and 3.0 Watts per square centimeter of substrate surface.
- the LF is supplied in a frequency range generally in the range of 100 KHz to 900 KHz, the low frequency energy level preferably being generally in the range of 0.5 Watts and 3.0 Watts per square centimeter of substrate surface.
- a suitable selected thickness for the a-F:C film deposited using the present invention is generally in the range of 1,000 angstroms to 10,000 angstroms, although the invention is not limited to any specific thickness range.
- the substrate and deposited fluorinated amorphous carbon is annealed.
- the present invention allows for annealing at a temperature greater than or equal to 440° C., although the process can be used with anneals of between 300° C. and 550° C.
- the duration of the anneal is a matter of design choice but will generally exceed 20 minutes and can be 2 hours or more, depending on the design and performance specifications of the integrated circuits being fabricated.
- FIG. 1 is a schematic depiction of a PECVD chamber for carrying out selected steps in the process of the present invention.
- FIG. 2 is a block diagram illustrating the steps in the process for depositing fluorinated amorphous carbon on a substrate in a PECVD chamber as shown in the FIG. 1, in accordance with the present invention.
- FIG. 3 is a block diagram illustrating a preferred embodiment of a process for depositing fluorinated amorphous carbon on a substrate in a PECVD chamber, carrying the process through to a final anneal.
- the present invention provides a process for depositing fluorinated amorphous carbon (a-F:C) on a silicon wafer or other substrate.
- the wafer substrate at the time the steps in the method are carried out, has been processed by well-known techniques (not shown) to produce integrated circuit (IC) features (e.g., transistors and other active and passive devices) on the wafer.
- IC integrated circuit
- the type and number of integrated circuit features on the substrate are unimportant to the process of the present invention, except that the low-k fluorinated amorphous carbon dielectric material is most advantageously employed on ultra-large-scale-integration (ULSI) high-density ICs.
- ULSI ultra-large-scale-integration
- the dielectric material is used in interconnect structures, such as conductive lines and vias (not shown) which are well-known conductive interconnect features typically formed in, and extend through, the interconnect dielectric film which is deposited on the wafer, including the a-F:C dielectric deposited in the method of the present invention.
- interconnect structures such as conductive lines and vias (not shown) which are well-known conductive interconnect features typically formed in, and extend through, the interconnect dielectric film which is deposited on the wafer, including the a-F:C dielectric deposited in the method of the present invention.
- the form, architecture, and conductive materials used in the interconnect structures, as well as the methods of forming such structures, are not described herein and are a matter of design choice well known to those skilled in the art.
- This invention relates to the method of forming a suitable low-dielectric-constant (low-k) dielectric film which is deposited on the wafer and is suitable for use between and around the conductive lines, vias, and other conductors in ULSI and similar ICs.
- low-k dielectric film which is deposited on the wafer and is suitable for use between and around the conductive lines, vias, and other conductors in ULSI and similar ICs.
- FIG. 1 is a schematic illustration of a suitable apparatus 10 for carrying out a plasma enhanced chemical vapor deposition (PECVD) on a substrate such as wafer 12.
- Apparatus 10 includes a PECVD chamber 16 of a size suitable for holding one or more wafers 12, which are supported in the chamber on a chuck 20.
- the interior 22 can be evacuated or pressurized as desired by a suitable pump and valve apparatus schematically illustrated in FIG. 1 by pump 26.
- Individual wafers 12 are moved in and out of chamber 16 by a suitable wafer handler 30 through a gate valve 32 in the chamber wall, allowing wafers to be moved onto chuck 20 for processing, and then removed from the chamber.
- Selected gases used in PECVD processing are introduced into the chamber through a suitable manifold system 36 from various gas supply reservoirs indicated collectively at 40, controlled by valves 42.
- the gases are introduced into the chamber through what is called a shower head 46, which distributes the gases as required.
- Chuck 20 can be heated to any desired temperature, the heating element for this purpose being schematically depicted as heater 50.
- the heater and chuck are used to select the temperature of wafer 12 during PECVD processing.
- Plasma energy is supplied to the chamber through an RF generator 52 which supplies high frequency (HF) RF power radiated through shower head 46.
- HF high frequency
- Apparatus 10 preferably also includes a low frequency (LF) generator 56 for supplying LF power to the interior of the chamber.
- LF power is applied between the chuck 20 and shower head 46 in a manner well known to those skilled in the art.
- LF power is used to increase crosslinking in the amorphous fluorinated carbon (a-F:C) film deposited on wafer 12 during PECVD processing.
- FIG. 2 illustrates the steps in the process of the present invention, which will be described with reference to FIGS. 1 and 2.
- a wafer substrate 12 is first positioned on chuck 20 in PECVD chamber 16 by wafer handler 30.
- the substrate 12 is typically a silicon wafer prepared for receiving a-F:C, the a-F:C being deposited on the upper surface 58 of the wafer.
- the first step shown in FIG. 2 is step 70, which is the heating of substrate 12 to a temperature above 200° C.
- wafer 12 is heated to a temperature generally in the range of 200° C. -300° C.
- the next step 76 is the introduction of a flow of fluorine containing gas (FCG) and carbon containing gas (CCG) into chamber 16 via manifold 36 from suitable supplies 40.
- FCG fluorine containing gas
- CCG carbon containing gas
- the preferred FCG is octafluorocyclobutane (C 4 F 8 ) and the preferred CCG is methane (CH 4 ).
- the ratio of FCG/CCG introduced into chamber 16 is selected to deposit a-F:C on substrate 12 by plasma enhanced chemical vapor deposition. The suggested ratio is between 1/1 and 30/1 (FCG/CCG) and, preferably, between 5/1 and 15/1.
- suitable plasma power is applied in chamber 16 (step 78).
- suitable plasma power includes HF energy (13.56 MHz), at an energy level of between 0.5 Watts and 3.0 Watts per square centimeter of substrate surface (i.e., the surface area of substrate 12), and LF energy, at a frequency generally in the range of 100 KHz 900 KHz, at an energy level of 0.5 Watts and 3.0 Watts per square centimeter of substrate surface.
- C 4 F 8 provides discharge of two kinds of long-life radicals.
- One is the fluorocarbon radical (CF x ) (wherein 1 ⁇ 2), which is the building block for a-F:C deposits.
- the other is F and F 2 atoms, which are destructive etchants that form volatile fluorides which weaken the a-F:C film deposited on substrate 12.
- the methane serves to discharge hydrogen (H) radicals, which can tie up F atoms by forming volatile HF, which reduces the etching from the F and F 2 atoms, thus improving the stability of the resultant a-F:C film deposited on the wafer.
- the deposition rate and the fluorine concentration of the a-F:C film are selectively controlled by the flow rates of the FCG and CCG gases, as well as the chamber pressure within chamber 16.
- the ratio of FCG to CCG is generally between 1 to 1 and 30 to 1 and is preferably between 5 to 1 and 15 to 1 (FCG to CCG).
- the ambient pressure maintained within chamber 16 during steps 76 and 78 is preferably generally in the range of 0.3 Torr to 2.0 Torr.
- the present invention further includes the additional step 80 of introducing silane (SiH 4 ) gas into chamber 16, together with the FCG and CCG gases, during steps 76 and 78.
- the percentage of silane introduced into chamber 16 during step 80 is preferably generally in the range of 1% to 15% of the total introduced gases (i.e., FCG and CCG and silane).
- the silane has been found to improve the thermal stability of the deposited a-F:C film.
- Thermal stability is generally defined as minimal-to-zero shrinkage (e.g., less than 1% shrinkage) of the deposited a-F:C film during the high temperature anneal which is carried out upon completion of the interlevel interconnects on an IC wafer. It is advantageous in IC wafer fabrication to be able to anneal the fabricated wafer at a temperature above 440° C. for a minimum of approximately 20 minutes, and preferably between 30 minutes and up to several hours.
- the anneal is generally a part of the completion process for the devices on the wafer.
- One significant problem with the use of a-F:C dielectrics on IC wafers has been its poor thermal stability during anneals over 350° C.-400° C.
- Fluorinated amorphous carbon films deposited using prior art processes, when subjected to higher temperature anneals (440° C.+) exhibit undesirable shrinkage, for example, 5%-20% or more.
- good thermal stability minimum or zero shrinkage at final anneals up to 440° C.-465° C.
- Greatly improved thermal stability is provided over a wider range of anneal temperatures, for example, between 300° C.-550° C.
- FIG. 3 shows an illustrative embodiment the process of the present invention, explaining the process in greater detail.
- the wafer 12 is positioned on chuck 20 in chamber 16 and heated to a temperature generally in the range of 200° C. to 300° C.
- gases C 4 F 8 , CH 4 , and SiH 4 are introduced into chamber 16 via supplies 40 and valves 42 and manifold 36.
- the gases are distributed in chamber 16 through showerhead 46.
- the flow rates of gases during step 102 are the rates required to maintain the ambient pressure within chamber 16 generally in the range of 0.3 Torr and 2.0 Torr.
- the ratio of C 4 F 8 to CH 4 (C 4 F 8 /CH 4 ) during step 102 is generally in the range of 1/1 to 30/1 and preferably between 5/1 and 15/1.
- the percentage of silane gas introduced in step 102, as a percentage of the three introduced gases C 4 F 8 , CH 4 , and SiH 4 is generally in the range of 1% to 15% SiH 4 .
- the flow of C 4 F 8 , CH 4 , and SiH 4 during step 102 can alternatively be characterized as flow rates measured in standard cubic centimeters per minute (sccm), per cubic meter of interior volume 22 in PECVD chamber 16.
- sccm standard cubic centimeters per minute
- the following are suitable flow rates (per m 3 of chamber volume) for carrying out step 102:
- step 104 is carried out by applying HF and LF plasma energy in chamber 16.
- the HF energy is at a suggested standard frequency of 13.56 MHz and at an energy level of between 0.5 Watts and 3.0 Watts per square centimeter of surface area 58 of substrate wafer 12.
- LF energy is applied at a frequency generally in the range of 100 KHz to 900 KHz at an energy level of between 0.5 Watts and 3.0 Watts per square centimeter of substrate surface.
- Steps 102 and 104 deposit a-F:C on wafer 12 (step 108).
- a suitable thickness of a-F:C film deposited in step 108 is generally in the range of 1,000 angstroms to 10,000 angstroms.
- wafer 12 is removed from chamber 16 by any suitable means, such as handler 30, and annealed (step 110) in a suitable annealing oven at a temperature generally in the range of 300° C. to 550° C.
- a suitable annealing oven at a temperature generally in the range of 300° C. to 550° C.
- the process exhibits good thermal stability (i.e., shrinkage of less than approximately 1%) at anneal temperatures above 440° C., generally in the range of 440° C.-465° C.
- a 6-inch wafer 12 was placed on chuck 20 and heated to a temperature of 250° C.
- a flow of C 4 F 8 , CH 4 , and SiH 4 gases was introduced into the chamber at the following flow rates
- HF power 13.56 MHz was applied at a power level of 200 Watts and LF power (500 KHz) was applied at 200 Watts.
- the ambient pressure in the chamber was maintained at approximately 0.4 Torr.
- the above conditions produced a deposition rate of a-F:C of 1,200 angstroms/minute. Deposition was carried out for four minutes. Then the wafer was removed from the chamber and a final anneal was carried out at 450° C. for 30 minutes.
- the resultant dielectric constant k of the a-F:C was approximately 2.3.
- the present invention has been found to improve the thermal stability and lower the dielectric constant of deposited a-F:C films formed by PECVD processes. Variations in the process are possible within the scope of the present invention. For example, the deposition temperature and ratio of gases specified in the experimental example are suggestive only. Within the specified ranges disclosed herein, it will be necessary to optimize the flow rates and temperatures used in IC manufacturing processes which are employed for commercial production.
Abstract
Description
TABLE I ______________________________________ Relevant properties for several members of carbon family Chemical Thermal Material Composition Structure k Stability ______________________________________ Diamond C Crystalline, fully Greater Very high crosslinked than 5 Hydro- C & H Amorphous 2.7-3.8 350- genated H: 30 at. %- polymer, 400°C. Carbon 50 at. % highly crosslinked (a-H:C) or Diamond- like Carbon (DLC) Fluor- C & F Amorphous 2.1-2.8 300- inated F: 40 at. %- polymer, 420° C. Amor- 50 at. % highly crosslinked phous Carbon (a-F:C) PTFE C & F (--CF.sub.2 --) 2.0 <300° C. or Teflon F: 67 at. % polymer, uncrosslinked ______________________________________
Claims (20)
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/023,382 US5900290A (en) | 1998-02-13 | 1998-02-13 | Method of making low-k fluorinated amorphous carbon dielectric |
JP10338211A JPH11251308A (en) | 1998-02-13 | 1998-11-27 | Low dielectric constant fluorinated amorphous carbon dielectric and formation method therefor |
TW087120344A TW414812B (en) | 1998-02-13 | 1998-12-08 | Low-k fluorinated amorphous carbon dielectric and method of making the same |
DE69933598T DE69933598T2 (en) | 1998-02-13 | 1999-01-21 | Low k fluorinated amorphous carbon dielectric, and method of making the same |
EP99300444A EP0936282B1 (en) | 1998-02-13 | 1999-01-21 | Low-k fluorinated amorphous carbon dielectric and method of making the same |
KR1019990003534A KR100283007B1 (en) | 1998-02-13 | 1999-02-03 | Low-k fluorinated amorphous carbon dielectric and method of making the same |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/023,382 US5900290A (en) | 1998-02-13 | 1998-02-13 | Method of making low-k fluorinated amorphous carbon dielectric |
Publications (1)
Publication Number | Publication Date |
---|---|
US5900290A true US5900290A (en) | 1999-05-04 |
Family
ID=21814764
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/023,382 Expired - Fee Related US5900290A (en) | 1998-02-13 | 1998-02-13 | Method of making low-k fluorinated amorphous carbon dielectric |
Country Status (6)
Country | Link |
---|---|
US (1) | US5900290A (en) |
EP (1) | EP0936282B1 (en) |
JP (1) | JPH11251308A (en) |
KR (1) | KR100283007B1 (en) |
DE (1) | DE69933598T2 (en) |
TW (1) | TW414812B (en) |
Cited By (26)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6147407A (en) * | 1998-03-27 | 2000-11-14 | Lucent Technologies Inc. | Article comprising fluorinated amorphous carbon and process for fabricating article |
US6184157B1 (en) * | 1998-06-01 | 2001-02-06 | Sharp Laboratories Of America, Inc. | Stress-loaded film and method for same |
EP1087036A1 (en) * | 1999-09-27 | 2001-03-28 | Tokyo Electron Limited | Method and apparatus for observing porous amorphous film, and method and apparatus for forming the same |
WO2001040537A1 (en) * | 1999-11-30 | 2001-06-07 | The Regents Of The University Of California | Method for producing fluorinated diamond-like carbon films |
SG81991A1 (en) * | 1999-05-25 | 2001-07-24 | Tokyo Electron Ltd | Method for producing insulator film |
US6296906B1 (en) | 1999-09-30 | 2001-10-02 | Novellus Systems, Inc. | Annealing process for low-k dielectric film |
US6303518B1 (en) | 1999-09-30 | 2001-10-16 | Novellus Systems, Inc. | Methods to improve chemical vapor deposited fluorosilicate glass (FSG) film adhesion to metal barrier or etch stop/diffusion barrier layers |
US6419985B1 (en) * | 1997-11-27 | 2002-07-16 | Tokyo Electron Ltd. | Method for producing insulator film |
US6458718B1 (en) | 2000-04-28 | 2002-10-01 | Asm Japan K.K. | Fluorine-containing materials and processes |
US6465372B1 (en) * | 1999-08-17 | 2002-10-15 | Applied Materials, Inc. | Surface treatment of C-doped SiO2 film to enhance film stability during O2 ashing |
US6486078B1 (en) | 2000-08-22 | 2002-11-26 | Advanced Micro Devices, Inc. | Super critical drying of low k materials |
US6602806B1 (en) | 1999-08-17 | 2003-08-05 | Applied Materials, Inc. | Thermal CVD process for depositing a low dielectric constant carbon-doped silicon oxide film |
US6632478B2 (en) | 2001-02-22 | 2003-10-14 | Applied Materials, Inc. | Process for forming a low dielectric constant carbon-containing film |
US6652969B1 (en) * | 1999-06-18 | 2003-11-25 | Nissin Electric Co., Ltd | Carbon film method for formation thereof and article covered with carbon film and method for preparation thereof |
US6770332B2 (en) * | 1997-11-20 | 2004-08-03 | Tokyo Electron Limited | Method for forming film by plasma |
US6773762B1 (en) * | 1997-11-20 | 2004-08-10 | Tokyo Electron Limited | Plasma treatment method |
US20040158024A1 (en) * | 2001-07-05 | 2004-08-12 | Kreisler Lau | Low dielectric constant materials and methods of preparation thereof |
US20040247896A1 (en) * | 2001-12-31 | 2004-12-09 | Paul Apen | Organic compositions |
US7060323B2 (en) * | 1996-08-29 | 2006-06-13 | Matsushita Electric Industrial Co., Ltd. | Method of forming interlayer insulating film |
US20060166491A1 (en) * | 2005-01-21 | 2006-07-27 | Kensaku Ida | Dual damascene interconnection having low k layer and cap layer formed in a common PECVD process |
US7101771B2 (en) | 2000-04-04 | 2006-09-05 | Micron Technology, Inc. | Spin coating for maximum fill characteristic yielding a planarized thin film surface |
DE102005034764A1 (en) * | 2005-07-26 | 2007-02-01 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Process for the preparation of functional fluorocarbon polymer layers by plasma polymerization of perfluorocycloalkanes |
US20100022033A1 (en) * | 2006-03-28 | 2010-01-28 | Lam Research Corporation | Process for wafer temperature verification in etch tools |
US20100093115A1 (en) * | 2006-03-28 | 2010-04-15 | Lam Research Corporation | Etch tool process indicator method and apparatus |
US9245967B2 (en) | 2009-10-14 | 2016-01-26 | Samsung Electronics Co., Ltd. | Semiconductor device including metal silicide layer and method for manufacturing the same |
CN110612596A (en) * | 2017-04-13 | 2019-12-24 | 应用材料公司 | Method and apparatus for depositing low dielectric constant films |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100541541B1 (en) * | 1999-08-26 | 2006-01-12 | 삼성전자주식회사 | Process Chamber of Plasma Process System |
JP4758938B2 (en) * | 2001-08-30 | 2011-08-31 | 東京エレクトロン株式会社 | Insulating film forming method and insulating film forming apparatus |
EP1568071B1 (en) * | 2002-11-29 | 2019-03-20 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Wafer comprising a separation layer and a support layer and its manufacturing method |
US9520372B1 (en) | 2015-07-20 | 2016-12-13 | Taiwan Semiconductor Manufacturing Company, Ltd. | Wafer level package (WLP) and method for forming the same |
KR20230169654A (en) | 2022-06-09 | 2023-12-18 | 충남대학교산학협력단 | High-k Amorphous Fluorinated Carbon Thin Films, Preparation Method thereof and Applications to Semiconductor or Capacitor Devices |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62180073A (en) * | 1986-02-03 | 1987-08-07 | Ricoh Co Ltd | Amorphous carbon film and its production |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2962851B2 (en) * | 1990-04-26 | 1999-10-12 | キヤノン株式会社 | Light receiving member |
CA2157257C (en) * | 1994-09-12 | 1999-08-10 | Kazuhiko Endo | Semiconductor device with amorphous carbon layer and method of fabricating the same |
JP2737720B2 (en) * | 1995-10-12 | 1998-04-08 | 日本電気株式会社 | Thin film forming method and apparatus |
-
1998
- 1998-02-13 US US09/023,382 patent/US5900290A/en not_active Expired - Fee Related
- 1998-11-27 JP JP10338211A patent/JPH11251308A/en active Pending
- 1998-12-08 TW TW087120344A patent/TW414812B/en not_active IP Right Cessation
-
1999
- 1999-01-21 DE DE69933598T patent/DE69933598T2/en not_active Expired - Fee Related
- 1999-01-21 EP EP99300444A patent/EP0936282B1/en not_active Expired - Lifetime
- 1999-02-03 KR KR1019990003534A patent/KR100283007B1/en not_active IP Right Cessation
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62180073A (en) * | 1986-02-03 | 1987-08-07 | Ricoh Co Ltd | Amorphous carbon film and its production |
Non-Patent Citations (12)
Title |
---|
Article titled, Low Dielectric Constant Materials for ULSI Interlayer Dielectric Applications by W. W. Lee and P.S. Ho, published in MRS Bulletin/Oct. 1997, pp. 19 23. * |
Article titled, Low-Dielectric-Constant Materials for ULSI Interlayer-Dielectric Applications by W. W. Lee and P.S. Ho, published in MRS Bulletin/Oct. 1997, pp. 19-23. |
Paper titled, "Diamondlike Carbon Materials as Low-k Dielectrics for Multilevel Interconnects in ULSI" by A. Grill, A. Patel, K.L. Saenger, C. Jahnes, S.A. Cohen, A.G. Schrott, D.C. Edelstein and J.R. Paraszczak, pulished in Mat. Res. Soc. Symp. Proc. vol. 443, 1997 Materials Research Society, pp. 155-164. |
Paper titled, "Fluorinated Amorphous Carbon Thin Films Grown from C4 F8 for Multilevel Interconnections of Integrated Circuits" by K. Endo, T. Tatsumi, Y. Matsubara and T. Horiuchi published in Mat. Res. Soc. Symp. Proc. vol. 443, 1997 Materials Research Society, pp. 165-170. |
Paper titled, "Two Approaches to the Development of Los K Systems; Parylene AF-4, and Fluorinated Amorphous Carbon" by A. Harrus, J. Kelly, D. Kumar, T. Mountsier and M.A. Plano presented at 52nd Semiconductor Symposium of the Japaneses ECS, pp. 76-81. |
Paper titled, "Ultra Low k Dielectric PECVD α-FC Films for Damascene Application" by S. Robles, P. Xu, W-F. Yau, J. Huang and K. Fairbairn presented at Advanced Metallization and Interconnect Systems for ULSI Systems Conf., Sep. 1997. No Page Number |. |
Paper titled, Diamondlike Carbon Materials as Low k Dielectrics for Multilevel Interconnects in ULSI by A. Grill, A. Patel, K.L. Saenger, C. Jahnes, S.A. Cohen, A.G. Schrott, D.C. Edelstein and J.R. Paraszczak, pulished in Mat. Res. Soc. Symp. Proc. vol. 443, 1997 Materials Research Society, pp. 155 164. * |
Paper titled, Fluorinated Amorphous Carbon Thin Films Grown from C 4 F 8 for Multilevel Interconnections of Integrated Circuits by K. Endo, T. Tatsumi, Y. Matsubara and T. Horiuchi published in Mat. Res. Soc. Symp. Proc. vol. 443, 1997 Materials Research Society, pp. 165 170. * |
Paper titled, Fluorocarbon Films from Plasma Polymerization of Hexafluoropropylene and Hydrogen, by T.W. Mountsier and D. Kumar, published in Mat. Res. Soc. Symp. Proc. vol. 443, 1997 Materials Research Society, pp. 41 46. * |
Paper titled, Fluorocarbon Films from Plasma Polymerization of Hexafluoropropylene and Hydrogen, by T.W. Mountsier and D. Kumar, published in Mat. Res. Soc. Symp. Proc. vol. 443, 1997 Materials Research Society, pp. 41-46. |
Paper titled, Two Approaches to the Development of Los K Systems; Parylene AF 4, and Fluorinated Amorphous Carbon by A. Harrus, J. Kelly, D. Kumar, T. Mountsier and M.A. Plano presented at 52 nd Semiconductor Symposium of the Japaneses ECS, pp. 76 81. * |
Paper titled, Ultra Low k Dielectric PECVD FC Films for Damascene Application by S. Robles, P. Xu, W F. Yau, J. Huang and K. Fairbairn presented at Advanced Metallization and Interconnect Systems for ULSI Systems Conf., Sep. 1997. No Page Number . * |
Cited By (39)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7060323B2 (en) * | 1996-08-29 | 2006-06-13 | Matsushita Electric Industrial Co., Ltd. | Method of forming interlayer insulating film |
US6773762B1 (en) * | 1997-11-20 | 2004-08-10 | Tokyo Electron Limited | Plasma treatment method |
US6770332B2 (en) * | 1997-11-20 | 2004-08-03 | Tokyo Electron Limited | Method for forming film by plasma |
US6419985B1 (en) * | 1997-11-27 | 2002-07-16 | Tokyo Electron Ltd. | Method for producing insulator film |
US6147407A (en) * | 1998-03-27 | 2000-11-14 | Lucent Technologies Inc. | Article comprising fluorinated amorphous carbon and process for fabricating article |
US6184157B1 (en) * | 1998-06-01 | 2001-02-06 | Sharp Laboratories Of America, Inc. | Stress-loaded film and method for same |
SG81991A1 (en) * | 1999-05-25 | 2001-07-24 | Tokyo Electron Ltd | Method for producing insulator film |
US6652969B1 (en) * | 1999-06-18 | 2003-11-25 | Nissin Electric Co., Ltd | Carbon film method for formation thereof and article covered with carbon film and method for preparation thereof |
US6602806B1 (en) | 1999-08-17 | 2003-08-05 | Applied Materials, Inc. | Thermal CVD process for depositing a low dielectric constant carbon-doped silicon oxide film |
US6465372B1 (en) * | 1999-08-17 | 2002-10-15 | Applied Materials, Inc. | Surface treatment of C-doped SiO2 film to enhance film stability during O2 ashing |
US6583497B2 (en) * | 1999-08-17 | 2003-06-24 | Applied Materials Inc. | Surface treatment of c-doped SiO2 film to enhance film stability during O2 ashing |
EP1087036A1 (en) * | 1999-09-27 | 2001-03-28 | Tokyo Electron Limited | Method and apparatus for observing porous amorphous film, and method and apparatus for forming the same |
US6528108B1 (en) | 1999-09-27 | 2003-03-04 | Tokyo Electron Limited | Method and apparatus for observing porous amorphous film, and method and apparatus for forming the same |
US6296906B1 (en) | 1999-09-30 | 2001-10-02 | Novellus Systems, Inc. | Annealing process for low-k dielectric film |
US6303518B1 (en) | 1999-09-30 | 2001-10-16 | Novellus Systems, Inc. | Methods to improve chemical vapor deposited fluorosilicate glass (FSG) film adhesion to metal barrier or etch stop/diffusion barrier layers |
WO2001040537A1 (en) * | 1999-11-30 | 2001-06-07 | The Regents Of The University Of California | Method for producing fluorinated diamond-like carbon films |
US20070004219A1 (en) * | 2000-04-04 | 2007-01-04 | John Whitman | Semiconductor device fabrication methods employing substantially planar buffer material layers to improve the planarity of subsequent planarazation processes |
US7202138B2 (en) | 2000-04-04 | 2007-04-10 | Micron Technology, Inc. | Spin coating for maximum fill characteristic yielding a planarized thin film surface |
US20070004221A1 (en) * | 2000-04-04 | 2007-01-04 | John Whitman | Methods for forming material layers with substantially planar surfaces on semiconductor device structures |
US7101771B2 (en) | 2000-04-04 | 2006-09-05 | Micron Technology, Inc. | Spin coating for maximum fill characteristic yielding a planarized thin film surface |
US6458718B1 (en) | 2000-04-28 | 2002-10-01 | Asm Japan K.K. | Fluorine-containing materials and processes |
US6486078B1 (en) | 2000-08-22 | 2002-11-26 | Advanced Micro Devices, Inc. | Super critical drying of low k materials |
US6632478B2 (en) | 2001-02-22 | 2003-10-14 | Applied Materials, Inc. | Process for forming a low dielectric constant carbon-containing film |
US20040158024A1 (en) * | 2001-07-05 | 2004-08-12 | Kreisler Lau | Low dielectric constant materials and methods of preparation thereof |
US7307137B2 (en) | 2001-07-05 | 2007-12-11 | Honeywell International Inc. | Low dielectric constant materials and methods of preparation thereof |
US20040247896A1 (en) * | 2001-12-31 | 2004-12-09 | Paul Apen | Organic compositions |
US20060166491A1 (en) * | 2005-01-21 | 2006-07-27 | Kensaku Ida | Dual damascene interconnection having low k layer and cap layer formed in a common PECVD process |
DE102005034764B4 (en) * | 2005-07-26 | 2012-08-02 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Process for the preparation of functional fluorocarbon polymer layers by plasma polymerization of perfluorocycloalkanes and substrates coated therewith |
US20090130330A1 (en) * | 2005-07-26 | 2009-05-21 | Fraunhofer-Gesellschaft Zur Foerderung Der Angerwandten Forschung E.V. | Method for producing Functional Fluorocarbon Polymer Layers by Means of Plasma Polymerization of Perfluorocycloalkanes |
DE102005034764A1 (en) * | 2005-07-26 | 2007-02-01 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Process for the preparation of functional fluorocarbon polymer layers by plasma polymerization of perfluorocycloalkanes |
US20100022033A1 (en) * | 2006-03-28 | 2010-01-28 | Lam Research Corporation | Process for wafer temperature verification in etch tools |
US20100093115A1 (en) * | 2006-03-28 | 2010-04-15 | Lam Research Corporation | Etch tool process indicator method and apparatus |
US7951616B2 (en) | 2006-03-28 | 2011-05-31 | Lam Research Corporation | Process for wafer temperature verification in etch tools |
US8206996B2 (en) | 2006-03-28 | 2012-06-26 | Lam Research Corporation | Etch tool process indicator method and apparatus |
US8492174B2 (en) | 2006-03-28 | 2013-07-23 | Lam Research Corporation | Etch tool process indicator method and apparatus |
US9245967B2 (en) | 2009-10-14 | 2016-01-26 | Samsung Electronics Co., Ltd. | Semiconductor device including metal silicide layer and method for manufacturing the same |
TWI562237B (en) * | 2009-10-14 | 2016-12-11 | Samsung Electronics Co Ltd | Semiconductor device including metal silicide layer and method for manufacturing the same |
CN110612596A (en) * | 2017-04-13 | 2019-12-24 | 应用材料公司 | Method and apparatus for depositing low dielectric constant films |
CN110612596B (en) * | 2017-04-13 | 2023-08-15 | 应用材料公司 | Method and apparatus for depositing low dielectric constant films |
Also Published As
Publication number | Publication date |
---|---|
KR100283007B1 (en) | 2001-02-15 |
DE69933598T2 (en) | 2007-08-23 |
TW414812B (en) | 2000-12-11 |
EP0936282B1 (en) | 2006-10-18 |
EP0936282A3 (en) | 2001-06-27 |
EP0936282A2 (en) | 1999-08-18 |
JPH11251308A (en) | 1999-09-17 |
KR19990072395A (en) | 1999-09-27 |
DE69933598D1 (en) | 2006-11-30 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5900290A (en) | Method of making low-k fluorinated amorphous carbon dielectric | |
US6440878B1 (en) | Method to enhance the adhesion of silicon nitride to low-k fluorinated amorphous carbon using a silicon carbide adhesion promoter layer | |
US6410462B1 (en) | Method of making low-K carbon doped silicon oxide | |
US5869149A (en) | Method for preparing nitrogen surface treated fluorine doped silicon dioxide films | |
US6991959B2 (en) | Method of manufacturing silicon carbide film | |
US6159871A (en) | Method for producing hydrogenated silicon oxycarbide films having low dielectric constant | |
US6919270B2 (en) | Method of manufacturing silicon carbide film | |
US6699784B2 (en) | Method for depositing a low k dielectric film (K>3.5) for hard mask application | |
US7030468B2 (en) | Low k and ultra low k SiCOH dielectric films and methods to form the same | |
US6632478B2 (en) | Process for forming a low dielectric constant carbon-containing film | |
US6448186B1 (en) | Method and apparatus for use of hydrogen and silanes in plasma | |
EP0934433B1 (en) | Method for depositing fluorine doped silicon dioxide films | |
KR20010075563A (en) | Silicon carbide deposition method and use as a barrier layer and passivation layer | |
US20050048795A1 (en) | Method for ultra low-K dielectric deposition | |
US6303519B1 (en) | Method of making low K fluorinated silicon oxide | |
US20040087179A1 (en) | Method for forming integrated dielectric layers | |
US6541400B1 (en) | Process for CVD deposition of fluorinated silicon glass layer on semiconductor wafer | |
US20040161946A1 (en) | Method for fluorocarbon film depositing | |
KR20010062216A (en) | Method and apparatus for reducing fixed charges in a semiconductor device | |
KR20210082265A (en) | 1-Methyl-1-iso-propoxy-silacycloalkane and high-density organosilica film prepared therefrom | |
US20020072248A1 (en) | Process of forming a low dielectric constant material |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: SHARP MICROELECTRONICS TECHNOLOGY, INC, WASHINGTON Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:YANG, HONGNING;NGUYEN, TUE;REEL/FRAME:008981/0576 Effective date: 19980213 |
|
AS | Assignment |
Owner name: SHARP KABUSHIKI KAISHA, JAPAN Free format text: ASSIGNMENT OF UNDIVIDED HALF INTEREST;ASSIGNOR:SHARP MICROELECTRONICS TECHNOLOGY, INC.;REEL/FRAME:009215/0949 Effective date: 19980506 |
|
AS | Assignment |
Owner name: SHARP LABORATORIES OF AMERICA, INC., WASHINGTON Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SHARP MICROELECTRONICS TECHNOLOGY, INC.;REEL/FRAME:009845/0188 Effective date: 19990330 |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
FPAY | Fee payment |
Year of fee payment: 8 |
|
REMI | Maintenance fee reminder mailed | ||
LAPS | Lapse for failure to pay maintenance fees | ||
LAPS | Lapse for failure to pay maintenance fees |
Free format text: PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES (ORIGINAL EVENT CODE: EXP.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20110504 |